[Killietalk] RE: Brine Shrimp Cyst discussion

["Koran, David HQ02" <David_Koran at hq02.usace.army.mil>]

As I read all of the back and forth on this topic one thing sticks out.
Think about the actual practice of hatching the cysts, we place them in a
salt water suspension and aerate the suspension.  To achieve a better hatch
rate on decapsulation you wet the cysts prior adding bleach.  If you store
the cysts in humid conditions the hatch rate decreases.

I interpret much of this as to "activate" the nauplii you need to wet the
"shell".  When you aerate, you thoroughly hydrate the outer covering.  As
long as you keep your "powder dry", the stuff works.  If you are freezing
your cysts, you are also greatly diminishing the relative humidity exposure
to the cysts.  Dry conditions--good long term storage, wetting the cyst
"capsule" (for lack of a better term) you establish the condition for
hatching.

Obviously, in the wild, the cysts floating or submerged in the GSL are in
this state.  However, hatching only begins once the water temperature rises
about the mid 50's.  Also, as the lake temperature plummets in fall, adult
shrimp lay resting eggs, maybe once again when they pass through this "switch
point".  Also as comparison I think of things like the seed bank at Colorado
State University where seeds are stored frozen but have to be "grown out
maybe every ten years as the seeds lose their viability over long term frozen
storage.  The same principle might be applicable to storing cysts frozen for
long periods of time.  I know it isn't this simple but dry is most important,
below 55 is secondary for storage, thorough wetting and hatching above 55
gets you hatching.  Hatching temperature then determines the average time
from which the cysts are sufficiently wetted until an acceptable percentage
of cysts hatch.  Things like bleach, bicarbonate, sulfate, etc., act as
control agents to address things that can effect the mortality of the newly
hatched shrimp such as bacteria maybe from improper cyst processing or
cleaning.  Hatching in a salt solution simply is creating the proper specific
gravity to maximize wetting.

OK, fire away...

Dave Koran


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